An optical pickup device is used for an optical disk drive that irradiates a disk such as a CD, a DVD, a Blu-ray disc, and an HD-DVD disc with a light beam spot to record and reproduce information made up of pit strings on the recording surface of the disk. An optical pickup device has an objective lens actuator for driving an objective lens used for forming a light beam spot.
In recent years, an optical disk drive focuses a light beam spot by using an objective lens having a high numerical aperture (high NA) and records and reproduces data having been recorded with high densities. Thus objective lenses having small inclinations relative to disks have been demanded.
In other words, for an objective lens actuator, a smaller tilt and a smaller reduction in the aberration of a light beam spot have been demanded. A tilt is a rotary motion made beyond a focusing direction and a tracking direction when a lens holder for holding an objective lens is driven.
Japanese Patent Laid-Open No. 2006-134411 discloses an optical pickup device for reducing a tilt, which is a rotary motion made other than a focusing direction and a tracking direction when a lens holder is driven, along with the configuration of a typical objective lens actuator.
First, the configuration of the typical objective lens actuator will be described below in accordance with an accompanying drawing. FIG. 12 is a perspective view showing the typical objective lens actuator according to the prior art. As shown in FIG. 12, an objective lens 51 is held by a lens holder 52 on which terminal plates 53 are fixed.
A fixed substrate 59 is fixed on a fixed part 57. One end 54b of each of a plurality of wires 54 serving as suspension members is fixed to the fixed substrate 59 by soldering with solder 56. The other end 54a of each of the plurality of wires 54 is fixed to the terminal plates 53 of the lens holder 52 by soldering with solder 55.
The objective lens 51 and the lens holder 52 (including the terminal plates 53) are formed integrally and constitute a moving part while being supported by the fixed substrate 59 with elasticity through the wires 54. The fixed part 57 has gaps serving as gel holder parts 58. The gaps are filled with damping gel (vibration damping gel) with the wires 54 passed through the gaps, and the damping gel damps the primary mode vibration of the moving part.
The moving part including the lens holder 52 can be driven in the direction of arrow Fo which is a focusing direction and in the direction of arrow Tr which is a tracking direction. The fixed part has a magnetic flux supply device (not shown) made up of a magnet and a yoke, and a plurality of coils (not shown) are fixed on the lens holder 52. By energizing the coils through the plurality wires 54, the objective lens 51 (the moving part including the lens holder 52) can be driven in a desired direction.
The foregoing explanation described the configuration of the typical objective lens actuator according to the prior art. In Japanese Patent Laid-Open No. 2006-134411, a technique using a conductive adhesive is disclosed instead of a fixing method using the solder 55 and the solder 56. The main configuration is substantially the same.